MEASUREMENT OF LOW-ENERGY COSMIC-RAY ANTIPROTONS AT SOLAR MINIMUM

The absolute fluxes of the cosmic-ray antiprotons at solar minimum are measured in the energy range 0.18 to 1.4 GeV, based on 43 events unam biguously detected in BESS 1995 data. The resultant energy spectrum ap pears to be flat below 1 GeV, compatible with a possible admixture of primary antiproton component with a soft energy spectrum, while the po ssibility of secondary antiprotons alone explaining the data cannot be excluded with the present accuracy. Further improvement of statistica l accuracy and extension of the energy range are planned in future BES S flights. [S0031-9007(98)07573-5].